<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>02_JS的变量与常量</title>
</head>
<body>
<script>
    //JS是一门弱类型语言
    var a = 10;
    console.log(a, typeof a);
    var b = 3.14;
    console.log(b, typeof b);
    var c = true;
    c = false;
    c = '我来了';
    console.log(c, typeof c);
    var c = "我又来了";
    console.log(c, typeof c);
    let x = 1;
    //let x= 66;//使用let声明的变量不可以重复声明！
    console.log(x, typeof x);
    const y = 3;
    console.log(y,typeof y);
    //y=2;//常量的值不允许被修改
</script>
</body>
</html>